Evolution D O N O W ! ! What is Evolution? How does Evolution Occur?

Evolution: A summary Evolution - The process of change over time Evolution applies to life and responds to the environment. Our Universe is billions of years old (9-12b years) Earth was created approx 4.5b years ago. Human existence is only a small fraction of time since the beginnings of the universe.

The Cosmic Calendar If the 12 billion year history of the universe was a string it would look like this!!! If the 12 billion year history of the universe was fit into a calendar year, it would look like this…..

Cosmic Calendar (From The Dragons of Eden - Carl Sagan) Pre-December Dates Big Bang January 1 Origin of Milky Way Galaxy May 1 Origin of the solar system September 9 Formation of the Earth September 14 Origin of life on Earth ~ September 25 Formation of the oldest rocks known on Earth October 2 Date of oldest fossils (bacteria and blue-green algae) October 9 Invention of sex (by microorganisms) ~ November 1 Oldest fossil photosynthetic plants November 12 Eukaryotes (first cells with nuclei) flourish November 15

DECEMBER First Worms. First oceanic plankton. Trilobite More Inverts Sunday Monday Tuesday Wednesday Thursday Friday Saturday 1 oxygen atmosphere develop on Earth. 2 3 4 5 vulcanism and channel formation on Mars. 6 7 8 9 10 11 12 13 14 15 16 First Worms. 17 Precambrian ends. Paleozoic Era and Cambrian Period begin. More Inverts 18 First oceanic plankton. Trilobite 19 Ordovician Period. First fish, First Verts 20 Silurian Period. First vascular plants 21 Devonian Period begins. First insects 22 First amphibiansFirst winged insect 23 Carboniferous Period. First trees. First reptiles. 24 Permian Period begins. First dinosaurs 25 Paleozoic Era ends. Mesozoic Era Begins. 26 Triassic Period. First mammals 27 Jurassic Period. First birds 28 Cretaceous Period. First flowers. Dinosaurs extinct. 29 Mesozoic Era ends. Cenozoic Era and Tertiary Period begin. First cetaceans. First primates. 30 First evolution of frontal lobes in the brains of primates. First hominids. 31 End of Pliocene Period. Quaternary (Pleistocene and Holocene) Period. First humans. DECEMBER December 31

December 31 ~ 1:30 p.m. Origin of ancestors of apes and men First hominids A. afarensis ~ 10:30 p.m. Widespread use of stone tools by Homo habilis 11:00 p.m. Domestication of fire by Homo erectus 11:46 p.m. Beginning of most recent glacial period. Homo Neanderthalis & Homo sapiens evolve 11:56 p.m. Seafarers settle Australia 11:58 p.m. Extensive cave painting in Europe 11:59 p.m. Invention of agriculture 11:59:20 p.m. Neolithic civilization; first cities. Colonization of North and South America across Bering straits 11:59:35 p.m. First dynasties in Sumer, Ebla and Egypt; development of astronomy 11:59:50 p.m. Invention of the alphabet; Akkadian Empire 11:59:51 p.m. Hammurabic legal codes in Babylon; Middle Kingdom in Egypt 11:59:52 p.m. Bronze metallurgy; Mycenaean culture; Trojan War; Olmec culture; invention of the compass Iron metallurgy; First Assyrian Empire; Kingdom of Israel; founding of Carthage by Phoenicia 11:59:53 p.m. Asokan India; Ch'in Dynasty China; Periclean Athens; birth of Buddha 11:59:54 p.m. Euclidean geometry; Archimedean physics; Ptolemaic astronomy; Roman Empire; birth of Christ 11:59:55 p.m. Zero and decimals invented in Indian arithmetic; Rome falls; Moslem conquests 11:59:56 p.m. Mayan civilization; Sung Dynasty China; Byzantine empire; Mongol invasion; Crusades 11:59:57 p.m. Renaissance in Europe; voyages of discovery from Europe and from Ming Dynasty China; emergence of the experimental method in science 11:59:58 p.m. science and technology; emergence of global culture;; first steps in spacecraft planetary exploration and the search of extraterrestrial intelligence 11:59:59 p.m.

You were born 11:59:59.999999999 seconds before new year

Darwin & Natural Selection Modern evolutionary thought arose through the inquiries of Charles Darwin. Darwin was a Naturalist aboard an exploration ship called the HMS Beagle. Collected and catalogued biological specimens for return to England.

The Voyage of the Beagle

Pictures of Galapagos Islands

The Galapagos Finches Darwin was fascinated by the species of Finches he observed in the Galopagos Islands. He found that these birds were quite similar to a species found on mainland South America. However they differed significantly in the shapes of their beaks. Darwin reasoned that these species of finches arose from a common ancestor, and gradually changed over time to accommodate their particular diets. This led him to develop his theory of evolution through Natural Selection

Darwin & Evolution 2 Theories of Evolution. Lamarckian Theory of Inheretance of Acquired Characteristics Held that traits acquired throughout life of an organism would be passed on to offspring. Eg. If you lifted weights during your life, your children would be stronger or, if you did'nt exercise your children would be weaker Theory has been replaced by Darwin's theory of natural selection. Darwin’s Theory of Natural selection: Based on following premises: There are not enough resources for all organisms to survive. Some organisms are more "fit" to survive. Fitness is: The ability of an organism to survive in its environment. The ability of an organism to survive long enough to reproduce. New genes/traits arise from random mutations. Most are either Neutral (no effect), or disadvantageous (decrease an organism's chance for survival).

Lamarck vs. Darwin

Natural Selection : The Peppered Moth: The peppered moth is a species of moth which uses camouflage against tree bark to avoid being eaten by birds. It is normally a light grey color. During England's industrial revolution, pollution caused a darkening of the bark of the trees. There was a natural variation in moth coloration with some being darker than others. Those moths of a lighter color, were easier to spot and eat by birds. And were eaten at a faster rate. The survivors tended to be darker, and when they mated, their offspring tended thus to be darker also. Over time, this resulted in the species becoming darker in color.

Effects of Natural Selection Natural selection can have many different effects on species appearance. These types of natural selection have been named as: Directional selection Stabilizing selection Disruptive selection

Directional Selection: Eliminates one extreme variation from an array of possible phenotypes. Results in a shift towards the other extreme.

Stabilizing Selection: Selection acts to eliminate both extremes of an array of phenotypes. Results in an increase in individuals exhibiting an intermediate phenotype.

Disruptive Selection Selection acts to remove the intermediate phenotypes favoring the extreme phenotypes:

Convergence Convergence occurs when species evolve into a common phentoypic form due to a common need. For example the following diagram shows a shark (fish), ichthyosaurus (reptile), a penguin (bird)and a dolphin (mammal). They all have a torpedo body shape, pectoral, caudal and dorsal fins. This is based on their common need to swim rapidly in an aquatic environment.

Divergence / Adaptive Radiation Divergence occurs when species evolve in several directions away from a common ancestor. This happens usually to fill a vacant ecological niche. Also known as adaptive radiation. Common Ancestor (First Mammal)

Convergence and Divergence Together By contrasting North American placental mammals with Australian marsupials. One can see how convergence and divergence works together. In each case an ancestor mammal evolved into several ecological niches. Since each niche required a specific phenotype, what results are 2 groups of mammals which have NEVER made contact, evolving into similar shapes.

Rates of Speciation: Two models exist to describe the rates of speciation. Gradualism: Refers to the model which holds that evolutionary change occurs in a gradual linear fashion. A species will change its morphology over time. Punctuated equilibrium Describes the process in which a species remains relatively unchanged for relatively long periods of time. Following which, a period of stress causes rapid change, followed by another period of relative stability.

Rates of Speciation:

Evidences of Evolution Fossils: Formed when animal remains are trapped in sedimentary layers. Organic material replaced by minerals over millions of years. Result is a "mineral cast" of the dead organism. Where a fossil is located in the sedimentary strata can indicate it's age. Successive changes in fossil forms of an organism can help in developing a fossil record of an organism's evolution. Some rare fossils can show "soft tissues" which give invaluable information on an organism's physiology Example: paleontologists recently discovered a dinosaur with a fossilized heart. This indicates that this species was most likely warm blooded. Fossilized Trilobite Fossilized Dinosaur Heart

Radiometric Dating: Based on the fact that radioactive materials decay at a fixed rate. Rate is known as a half-life: The amount of time in which only 1/2 of a radioactive sample remains By measuring the amount of radioactive material in a fossil, one can determine how old it is. Example is 14C dating. 14C is an isotope of 12C which radioactively decays to 14N. It occurs naturally in the environment, and is ingested by organisms while alive. Once an organism dies, 14C intake stops, and the 14C begins to decay One can then measure the amount of 14C remaining in a sample, and determine its age.

Similarities in Embryological Development In early embryo development, it appears that embryos "play out" their evolutionary history. we have not "forgotten" our evolutionary history, only built upon it.

Homologous Structures Refers to the fact that organisms' structures are formed from similar anatomy. Example the wing of a bird, arm of a man, wing of a bat, and flipper of a whale, all appear to be formed from a common set of bones. Implies that these organisms evolved from some common ancestor.

Amino Acid Differences Molecular studies of genetic similarity support estimates of evolutionary relationship from the fossil record and anatomical studies. Many independent lines of evidence all support the conclusion that all living things share common ancestors.

Vestigal Structures: Refers to the fact that organisms have structures which are disused These structures, however, a remnants of structures the organisms used earlier in their evolutionary history. Examples: Hip bones in whales Tail in humans Appendix in humans Legs/hips in snakes

Human Vestigial Structures

Analogous and Homologous Structures Analogous Structures- Same function, but different structure Homologous Structures- Different Functions, but the same structures